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PubMedDate not supplied

[Bonchodynamic tests in the study of bronchial asthma].

One characteristic of chronic obstructive bronchopneumopathies, especially bronchial asthma, is the slowing down of respiratory flow. Spirographic studies are therefore valued highly among specialists in respiratory pathology. All of those working in this field of physiopathology, however, agree that broncodynamic provocation tests are not fully specific for bronchial asthma. One important problem is the difficulty in determining the quantity of product inhaled by the patient, making the test even less precise. With our method, based on the broncotest developed by Piglowski, we are able to determine the quantity of inhaled material with a fairly high degree of accuracy. It thus represents a quantitative study and is much more specific. One hundred patients with bronchial asthma, whose ages ranged from 14 to 60 years, were selected for this study. We found that 100% of them (except for one 16-year-old patient whose case has been commented on) were positive for the acetylcholine aerosol test and for beta-2adrenergics (phenotherol). These results enabled us to establish diagnostic patterns for the severity of bronchial hyperactivity in relation to the number of micrograms needed to provoke a 20% variation in the VEMS. We consider it very important to determine the threshold does of acetylcholine, since it may serve in both diagnosis and prognosis. We believe that this method may represent a new direction in pharmacodynamic examination of asthma patients.

Acetylcholine↗
PubMed1979

Reproducibility of the response to diluent challenge in adult asthma.

The authors have demonstrated that patients with bronchial asthma may react to diluent provocative challenge. The pattern of airway response to diluent was found to be reproducible. The data herewith presented suggest that the baseline airway obstruction in adult asthma is highly variable but the degree of baseline obstruction is not related to the response to diluent challenge.

Administration, Intranasal↗
PubMedDate not supplied

[Study of the links between functional and clinical data in 212 asthma patients from 14 to 30 years old at a health spa in La Bourboule (author's transl)].

212 asthma patients, who attended their first health spa at La Bourboule, are studied. The functional data are statistically compared to those obtained from clinical examination. In this group of patients, it is found that: 1. Most of the functional tests are perturbed in proportion to the seiousness of the disease (determined by the number of days of attack per year). On the contrary, the other clinical criteria, and in particular the evolution time, do not affect the functional values. 2. The different ventilatory parameters studied are correlated two by two, for instance V 50 on the one had, FEV1, FEV1/VC or LR on the other. Finally the authors discuss the interest of V 50 and LR measurement in order to localize the bronchial obstruction in asthma at the level of either the large trunks (LR) or the small bronchii (V 50).

Adolescent↗
PubMed1979

Density dependence of the maximal expiratory flow volume curves in normal and asthmatic children.

We have studied the maximal expiratory flow volume curves with air and with an 80% helium-oxygen mixture, using 12 normal and 33 asthmatic children chosen according to clinical, functional and immunological criteria. In the normal children, the average delta Vmax (difference between the maximal flow in HeO2 and in air at corresponding lung volumes) was 49% and was similar from 60% to 20% of vital capacity. The iso flow volume (lung volume level at which the HeO2 and air flow volume curves intersect) was 3% of vital capacity. Eleven of the asthmatics were non-responders to the helium mixture (no significant differences in flow between HeO2 and air curves), five at 50% and 25% VC and six at only 25% VC. The other 22 asthmatics were responders, but nine of them showed a rise of the iso flow volume. Eight subjects showed no obstruction according to the flow volume curves in air; three of these had an abnormal response to the helium mixture. All the non-responders at 50% VC and half of the non-responders at 25% VC had a clinical history of recurrent infections. These results suggest, firstly, that when there is no history of recurrent infections, the site of obstruction in asthmatic children is mainly central. This does not exclude a coexisting peripheral obstruction which could persist after recovery of the central component. Secondly, by studying the HeO2 response at 25% VC, we can get more information than by measuring only the delta Vmax50 or iso flow volumes.

Adolescent↗
PubMedDate not supplied

Disturbances in pulmonary mechanics during serotonin perfusion.

The effect of i.v. perfused serotonin (75 microgram.kg-1.min-1) on bronchomotor tone was assessed in dogs by mechanical studies, with the result in an increase in total lung resistance. The increased residual volume (RV), closing capacity (CC) and slope of phase III (nitrogen single-breath washout) as well as the reduction of the helium response at low lung volumes suggest a peripheral action of the drug. Because of the large increase in total lung resistance and the decreased dead space (VD), bronchoconstriction of large airways must also be present. Vagal tone inhibition is incomplete whether by volume history or bilateral vagotomy and could be limited mainly to a segment which is situated between the equal pressure point and the most peripheral airways: maximal flows during partial expiratory flow-volume manoeuvres (PEFV) are lower than during maximal expiratory flow-volume manoeuvres (MEFV) and the volume of isoflow is higher in PEFV than in MEFV manoeuvers, suggesting that full inspiration reduces the bronchoconstriction induced by serotonin. On the other hand, the bilateral vagotomy did not reverse CC, RV, slope of phase III or VD back to control values. Isoproterenol i.v. injection improved all physiological measurements almost to the level of control values: beta-adrenergic stimulating drugs seem to inhibit completely serotonin induced bronchospasm, at all levels of the bronchial tree.

Airway Resistance↗
PubMed1979

[Interest of helium-oxygen flow volume and isoflow volume curves in chronic obstructive lung disease (author's transl)].

We have compared changes in maximal flows induced by breathing gases of different density in 54 patients suffering from emphysema and chronic bronchitis. We considered as positive responders those subjects displaying an increase by at least 20% of maximal expiratory flows while breathing gases of lower density. Such a response was demonstrated in 21 cases, the remainder (33 cases) being non-responders. Hence, in such patients, airways obstruction may primarily be localised in central or peripheral airways. There was no correlation between the nature of this response and the clinical diagnosis, but non-responders, in general, were those in whom respiratory insufficiency was more severe. There seemed to be no additional information gained by measuring isoflow-volume (iso V vol.) in comparison with measuring differences in maximal flows at 50% of vital capacity.

Bronchitis↗
PubMed1978

Indications for pulmonary function testing.

Pulmonary function testing is needed to determine the pathophysiology present in the patient with cardiopulmonary disease. Blood gases and pH should be obtained during emergency situations and during cranial, thoracic, and extensive cervical or abdominal surgery. Lung function tests can be divided in global such as spirometry and diffusing capacity which study the ventilation and transfer of gases and regional determinations of ventilation and perfusion. Both types of tests complement each other and should be used together. The spirometry should consist at least of determination of the vital capacity and is determined in the first second to ascertain if there is obstructive lung disease. Some tests such as flow-volume curves, alveolar-arterial gradients and closing volume are very useful to detect early pulmonary disease before any symptoms or findings are present. This is probably one of the most important medical indications for pulmonary function testing. Before certain types of surgery pulmonary function testing is indicated; if the spirometry and diffusing capacity tests are normal, there is no pulmonary contraindication for the planned surgery. In chest surgery if there is significant compromise of the spirometry and diffusing capacity regional lung function tests are indicated to study the pathophysiology at regional level, thus trying to circumscribe the lung resection to the diseased areas.

Blood Gas Analysis↗
PubMed1979

Correlation between the function and structure of the lung in smokers.

To study the relationship between morphologic changes and alteration of lung function, the excised lobes of 21 smokers and one nonsmoker who required lobectomy for small peripheral tumors were inflated and fixed in formalin, and measurements of bronchiolar narrowing and degree of emphysema were made. All patients had comprehensive pulmonary function tests (including diffusing characteristics, the single-breath N2 test, measurements of elastic recoil, and flow-volume measurements with air and helium) performed before lobectomy. Eight of the lobes excised from the smokers had emphysema of grade 15 or more, the greatest being grade 50. Lobes from 11 patients had evidence of airway narrowing. There were 6 lobes with both emphysema and airway narrowing. Pulmonary function was abnormal in some aspect in all lobes except that from the nonsmoker. Whereas the tests of diffusing capacity, particularly the fractional uptake of CO, correlated with the degree of emphysema, the tests of elastic recoil were not predictive of this early degree of emphysema. The degree of small-airway narrowing correlated with maximal mid-expiratory flow rate and the single-breath N2 test. The maximal flow/static recoil pressure curves were the most sensitive indicators of airway abnormality in the patients with emphysema.

Aged↗
PubMedDate not supplied

[Technical and experimental study of two electronic spirometers (author's transl)].

Two electronic spirometers which use standard pneumotachographs were evaluated for their static and dynamic response, and clinically compared in 20 subjects to a reference flow channel. In the Pneumoscreen the data are digitalized and stored, permitting to play back the flow-volume curves at low or high speed. The instrument provides a direct read-out of forced vital capacity and of five indexes of forced expiration. It was found perfectly adequate with respect to linearity and frequency response. However, due to some systematic error in digital processing, maximum flow at low lung volumes appeared substantially over-estimated. Besides forced vital capacity and a number of indexes of forced expiration, the Medistor type M 010 may be used to measure ventilation, tidal volume, frequency and maximum breathing capacity. The data are processed by an analog computer. The transducer was found poorly linear with inadequate frequency response. However, no systematic bias in the measurements was found, except for peak flow and maximum breathing capacity.

Airway Obstruction↗
PubMedDate not supplied

Tests of minimal obstruction in the small airways: interrelationships and physiologic significance.

Several technics have become popular to detect airway obstruction in the small (less than 2 mm diameter) peripheral bronchi which appear to be the site of the early lesions in chronic obstructive pulmonary disease (COPD). These include determining maximal midexpiratory flow rate (MMFR) from the expiration spirogram, maximum expiratory flows at low lung volumes from the maximum expiratory flow-volume (MEFV) curve, a comparison of flow-volume curves during air and helium/O2 breathing, demonstration of frequency dependence of compliance, and the measurement of closing volume (CV). This discussion attempts to interpret the literature relative to these tests, examining their physiologic basis and clinical significance while relating them to the standard spirometric tests. The aim is to provide the clinical anesthesiologist with a better understanding of the information they provide, since their physiologic basis relates well to the many aspects of abnormal lung function which appear during anesthesia and the entire perioperative period.

Airway Obstruction↗